Coverage extension level for coverage limited device

ABSTRACT

Generally discussed herein are systems, apparatuses, and methods that can provide a coverage enhancement to a coverage limited device. According to an example a method can include determining a received signal strength of a reference signal transmitted from a base station, determining a coverage enhancement based on the determined signal strength, or transmitting a signature sequence of a plurality of signature sequences a first repeated number of times corresponding to the determined coverage enhancement.

RELATED APPLICATION

This application claims the benefit of priority under 35 U.S.C. 119(e)to U.S. Patent Application Ser. No. 61/863,902, filed on Aug. 8, 2013,which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

Examples discussed herein generally relate to device or cellular networkcoverage enhancement. More specifically, examples generally relate torepeating a transmission of Master Information Block (MIB) for coverageenhancement.

BACKGROUND

Machine-Type Communication (MTC), sometimes referred to asmachine-to-machine (M2M) communication, is a promising and emergingtechnology to help enable a ubiquitous computing environment towards theconcept of an “Internet of Things” (an internetworking of things). MTCenables machines to communicate directly with one another.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralscan describe similar components in different views. Like numerals havingdifferent letter suffixes can represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 shows a block diagram of an example of a wireless network inaccord with one or more embodiments.

FIG. 2 shows a table detailing an example of coverage enhancementoptions available to a device in accord with one or more embodiments.

FIG. 3 shows a block diagram of an example of network resourcesallocated for providing coverage extension to a device in accord withone or more embodiments.

FIG. 4 shows a block diagram of another example of network resourcesallocated for providing coverage extension to a device in accord withone or more embodiments.

FIG. 5 shows a block diagram of yet another example of network resourcesallocated for providing coverage extension to a device in accord withone or more embodiments.

FIG. 6 shows a flow diagram of an example of a method for getting acoverage enhancement in accord with one or more embodiments.

FIG. 7 shows a block diagram of an example of a wireless device inaccord with one or more embodiments.

DESCRIPTION OF EMBODIMENTS

Examples in this disclosure relate generally to a mechanism forindicating a coverage extension level for an MTC. More specifically,examples relate to using a Physical Random Access Channel (PRACH)transmission to indicate a coverage extension level for an MTC device.

People and machines excel at different types of tasks. Machines arebetter at repetitive, well-defined operations, whereas people are betterat operations that include insight, inference, interpretation, oroperations that are not well-defined. Also, the speed at which a personcan perform an operation can be slower than a machine can perform thesame operation, or vice versa. As computing capabilities and technologyevolve, a machine can become capable of performing an operation that amachine previously was not able to perform. Getting a machine to performthe operation can be more cost effective than having a person performthe operation, because a person is typically an hourly cost, while amachine is a one-time cost (plus maintenance cost). By replacing theperson with a machine, the person can be freed to perform an operationthat a machine cannot currently perform.

Existing mobile broadband networks (e.g., cellular networks) weredesigned to optimize performance mainly for human type ofcommunications. The current networks are not optimized for MTC specificrequirements. For instance, some MTC devices are installed in basementsof residential buildings and these devices would experiencesignificantly greater penetration losses on the radio interface than anetwork device on a street, for example. In order to help providesufficient coverage of such MTC devices, special coverage enhancementconsiderations can be made, such as by using various physical channels.

Note that not all the MTC devices are located in a coverage holerequiring the worst case coverage enhancement target and some MTC device(e.g., User Equipment (UE)) may not need the coverage improvement or maynot need the maximum coverage improvement to communicate with a basestation (e.g., an eNodeB). Thus, to save resources or power, it can beadvantageous to provide a variety of coverage level extensions based onthe needs of the varying MTC devices and their locations.

Potential MTC based applications include smart metering, healthcaremonitoring, remote security surveillance, intelligent transportationsystem, among others. These services and applications can help stimulatethe design and development of a new type of MTC device that can beintegrated into current and next generation mobile broadband networks,such as Long Term Evolution (LTE) or LTE-Advanced (LTE-A).

FIG. 1 shows a block diagram of an example of a portion of a cellularnetwork 100, according to one or more embodiments. The cellular networkcan include a base station 102 communicatively coupled to one or moredevices 104A, 104B, 104C, or 104D.

The base station 102 can include a radio transceiver. The base station102 can receive UpLink (UL) data or a DownLink (DL) request from thedevice 104A-D. The base station 102 can transmit DownLink (DL) data or aUL request to the device 104A-D. The base station 102 can include aneNodeB, such as when the network 100 is an LTE network. The transceiverof the base station 102 can provide an interface for devices 104A-D tocommunicate to one another or a data network.

The device 104A-D can include a radio transceiver configured tocommunicate with the radio transceiver of the base station 102. Thedevice 104A-D can include a phone (e.g., a smart phone), a laptop, atablet, a personal digital assistant, a desktop computer, or an MTCdevice, among others. In the example where the network is an LTEnetwork, the device 104A-D can include UE.

An MTC device is an automatically-controlled (e.g., controlled withouthuman interference or interaction after deployment, other thanmaintenance) or unattended device. Examples MTC devices include a smartfridge that can measure temperature or pressure in the fridge or make adecision on the quality of food in the fridge, telematics (i.e. trackingof vehicles), security devices (e.g., cameras or motion detectors),meter readers, payment machines, vending machines, monitoring devices(e.g., heart rate, oxygen, air quality, blood-glucose, among others),among many others.

An MTC device is distinguished from a human communications device. Ahuman communications device provides services such as voice calling,messaging, or web browsing. MTC devices may not provide such services.

Each of the devices 104A-D illustrated in FIG. 1 can have differentrequirements for coverage extension levels, such as can include nocoverage extension needed to a maximum coverage extension level needed,and any coverage extension in between. For example, a device 104A-Dlocated in a basement can require a coverage extension level in order tocommunicate with the base station 102, while a device 104A-D outside ona street can have no requirement for a coverage extension to communicatewith the base station 102. To help reduce radio resource waste anddevice 104A-D or base station 102 power consumption, it can beadvantageous for the device 104A-D to indicate to the base station 102how much coverage extension the device 104A-D needs to reliablycommunicate with the base station 102.

The device 104A-D can indicate the coverage extension level to the basestation 102 using a PRACH transmission. A RACH is used by the device104A-D on a Time Domain Multiple Access (TDMA) enabled network. Thenetwork 100 can be operable to accommodate TDMA, Frequency DomainMultiple Access (FDMA), or Code Domain Multiple Access (CDMA). The RACHis generally used by the device 104A-D to communicate with the basestation 102 to synchronize the device's transmission with the basestation. Communications using the RACH are not scheduled, access to theRACH is random and access collisions can occur. The RACH is atransport-layer channel and the corresponding physical-layer channel isa PRACH.

In LTE and LTE-A systems, RACH is mainly used for the device 104A-D toachieve UL time synchronization. In particular, a RACH procedure can beused for initial access to establish a radio link, resource request whenno UL radio resource has been allocated, scheduling request if nodedicated scheduling request has been configured, or re-establishing aradio link after failure, among others.

The process of using a RACH can be classified into two operationalmodes: contention based and contention free RACH access. The former isapplied to the device 104A-D in idle state while the latter is used whenthe device 104A-D is in a connected state. In the contention based modeof operation, the device 104A-D generally selects one preamble signatureat random to transmit the PRACH communication. Note that disjointsubsets of signature sequence are currently allocated for contentionbased and contention free PRACH access in LTE.

For a device 104A-D that needs a coverage extension to reliablycommunicate with the base station 102, repeated sending of a PRACHpreamble or sequence in the time domain can be an effective way toimprove the coverage. The repeated transmissions can accumulate moreenergy and can provide a mechanism for the communication to be receivedat the base station 102. The starting sub-frame or repetition time(e.g., time between repeated communications) can be defined. Thestarting sub-frame or repetition time can be provided by higher layersignaling. Frequency hopping in one transmission or retransmissionattempt can be used to further enhance the detection performance. Theresulting repetition levels to achieve a coverage enhancement target candepend on the link level performance data (e.g., number of repetitionsto achieve a reliable transmission).

Not all devices 104A-D need the worst case coverage enhancement, or anycoverage enhancement in some cases. To support the scalability ofspectral efficiency impact for coverage improvement, PRACH transmissioncan be considered as a potential candidate by utilizing variousrepetition levels to inform the base station 102 on the amount ofcoverage enhancement the device 104A-D needs. In this manner,unnecessary device 104A-D power consumption and resource waste can beavoided or reduced. Supporting a relatively small number of repetitionlevels can be desirable to strike a proper balance between system levelperformance and detection complexity at the base station 102.

PRACH resources can be reserved for or used by MTC devices and otherPRACH resources can be reserved for legacy devices. Such a configurationcan help reduce a probability of a collision between the legacy devicesand the MTC devices. Variable PRACH resource configurations can be usedto help the base station 102 identify the devices 104A-D with differentrepetition levels, and consequently necessary coverage enhancement thatdevice 104A-D needs.

Some considerations in allocating PRACH resources for MTC or legacydevices can include base station detection complexity, collisionprobability, or access latency, among others.

PRACH resources can be multiplexed in the time or frequency domain orwith a non-overlapping subset of a signature sequences, or a combinationthereof. While multiplexing the PRACH resources in the frequency domaincan be attractive from the device's perspective due to low accesslatency, frequency domain multiplexing can increase a processing burdenat the base station since the base station can be required to detectmultiple PRACHs in one subframe. When PRACH resources are multiplexed inthe time domain, the base station processing complexity can remainvirtually unchanged at the expense of the increased access latency forthe device. When using a non-overlapping subset of sequences allocatedfor PRACH resources, the base station processing complexity can remainapproximately the same, but at the cost of a possible increase incollisions.

FIG. 2 illustrates an example of a table 200 that defines a gain (e.g.,a coverage extension) and the number of times the device 104A-D cantransmit (e.g., repetitions) a communication to achieve the gain,according to one or more embodiments. The table 200 supports threerepetition levels between the PRACH repetition numbers and differentcoverage enhancement targets. In this example, three PRACH repetitionlevels (i.e. two, ten, and forty repetitions) are considered, whichcorrespond to gains of 5 dB, 10 dB, and 15 dB, respectively. It will beunderstood that different numbers of repetition levels and coverageenhancement targets can be used and supported based on the example ofFIG. 2. For example, the base station 102 or the device 104A-D can beconfigured to transmit using one of five repetition levels or one of tenrepetition levels, which each correspond to different signal gains orcoverage extensions.

Information detailing the different repetition levels supported by aparticular base station can be broadcast to devices in the coverage area(e.g., cell) of the base station. The different repetition levelssupported by a base station can be predefined.

FIG. 3 shows a block diagram of an example of network resources 300allocated for providing coverage extension to a device, according to oneor more embodiments. The network resources 300 can include PRACHresources 304A, 304B, 304C, or 304D. The PRACH resources 304A and 304B-Dcan be allocated orthogonally in the time domain, such as to provide thePRACH resources 304A that support legacy devices orthogonal to the PRACHresources 304B-D in the time domain, such as shown in FIG. 3. FIG. 3illustrates an example of PRACH resource allocation that provides forthree different coverage extensions, each coverage extensioncorresponding to a respective PRACH resource 304B-D. The PRACH resources304A-D of FIG. 3 are illustrated as being configured to operate (receiveor transmit) on the same frequency band, while the PRACH resources 304Aare configured to operate at a different time period than the PRACHresources 304B-D, such as to make the PRACH resources 304B-D orthogonalto the PRACH resources 304A in the time domain.

PRACH resources 304B-D can each be allocated for different repetitionlevels. As shown in FIG. 3, the PRACH resources 304B-D can each providea coverage extension that corresponds to a different number ofrepetitions (e.g., number of times the device transmits a sub-frame,preamble, frame, or communication). The PRACH resources 304B-D can bemultiplexed using non-overlapping subset of signature sequences. Forexample, the PRACH resource 304B can include a subset of signaturesequences that does not include any same signature sequence as any ofthe signature sequences in the subset of signature sequences of thePRACH resource 304C or 304D.

The starting subframe, subset of signature sequences, repetition level,or the frequency position of PRACH resources 304A-D can be configurableor predefined. The configuration can be signaled (e.g., by broadcast orRadio Resource Control (RRC) signaling), such as by the base station102. The PRACH resource 304B-D for a coverage limited device can beallocated with a long periodicity. Such a configuration can help reducean impact on legacy device access to the PRACH resources 304A. In one ormore embodiments, non-overlapping sets of Physical Resource Block (PRB)resources (e.g., in the frequency or time domain) can be used in placeof non-overlapping subsets of signature sequences.

FIG. 4 shows a block diagram of another example of network resources 400allocated for providing coverage extension to a device, according to oneor more embodiments. The network resources 400 can include PRACHresources 402 or 404A, 404B, and 404C.

FIG. 4 illustrates PRACH resources 402 and 404A-C that are allocatedseparately in the frequency domain. The PRACH resource 402 can beallocated to a first frequency band and the PRACH resources 404A-C canbe allocated to a second, different or non-overlapping frequency band.In one or more embodiments, the PRACH resources 402 can be allocated fora legacy device and the PRACH resources 404A-C can be allocated for acoverage limited device, such as an MTC device. The PRACH resources404A-C can each be allocated for different repetition levels. The PRACHresources 404A-C can be multiplexed and each PRACH resource 404A-C caninclude a subset of signature sequences that is different ornon-overlapping with the other PRACH resources 404A-C.

A PRACH resource allocation scheme, like the one shown in FIG. 4, canprovide a scheme that does not significantly increase device complexity,but does increase the computation or hardware complexity for detectionat the base station increases.

Similar to the embodiments as described with regard to FIG. 3, thesubset of signature sequences can be supplanted with PRB resources. Sucha configuration can allow the PRACH resources 404A-C to usenon-overlapping PRB resources, respectively.

Similar to FIG. 3, FIG. 4 shows an embodiment with three differentextension levels, on corresponding to each PRACH resource 404A-C. Itwill be understood that fewer or more extension levels can be provided,such as by separating signature sequences or PRB resources into fewer ormore (non-overlapping) subsets. Also, FIG. 4 shows that the subset ofsignatures dedicated to coverage limited devices use the same frequencyband, however it will be understood that separate or non-overlappingsubframes or frequency bands can be dedicated to a different subset(s)of signature sequences. That is multiple separate or non-overlappingsubframes or frequency bands can be dedicated to human typecommunication devices, MTC devices, or coverage limited devices.

FIG. 5 shows a block diagram of another example of network resources 500allocated for providing coverage extension to a device, according to oneor more embodiments. The network resources 500 can include PRACHresources 502A, 502B, 502C, and 502D.

As shown in FIG. 5, PRACH resources 502A-D can be allocated separatelywith different (e.g., non-overlapping or disjoint) subsets of signaturesequences for coverage limited devices with different repetition levelsand for legacy devices. FIG. 5 shows an embodiment in which thesignature sequences have been split into four subsets, one subset ofsignature sequences for each of the PRACH resources 502A-D. The subsetsof signature sequences can include the same number or different numbersof signature sequences. For example, in a situation where relatively fewdevices need coverage enhancement, more signature sequences can beallocated for devices that do not need coverage enhancement.

FIG. 6 shows a flow diagram of an example of a method 600 for indicatinga coverage extension level, according to one or more embodiments. ThePRACH resource can be used to inform the base station on the amount ofcoverage enhancement a device needs.

The method 600, as illustrated in FIG. 6, can be performed by themodules, components, devices, or systems described herein. 600 includes:measuring a Reference Signal Received Power (RSRP) or an estimated pathloss between a base station and a device at operation 602; determining acoverage extension level based on the measured RSRP or estimated pathloss at operation 604; determining a repetition level based on thedetermined coverage extension at operation 606; and transmitting asignal a number of times corresponding to the repetition level atoperation 608. The method 600 illustrates operations from the device'sperspective and it will be understood that a method, according to one ormore embodiments, can include operations from the base station'sperspective.

RSRP is an average power of resource elements that carry a Cell-specificReference Signal (CRS). The device can measure the RSRP and estimate thepath loss between base station and the device based on the RSRP or CRStransmit power.

The operation at 604 can include determining the needed coverageextension level (e.g., a required gain, such as in dB) or the repetitionlevel, based on predefined or broadcasted mapping rules as describedabove (see FIG. 2 for example). The device can look up the neededcoverage extension level in a table, such as that shown in FIG. 2, anddetermine the number of repeated transmissions (the repetition level)that correspond to the coverage extension level.

In one or more embodiments, in an instance where the device determinesthat it needs a coverage extension level that is not supported by thenetwork, the device can determine the next closest coverage extensionlevel that is supported. The next closest coverage extension level caninclude a gain that is greater than the coverage extension level that isnot supported, so as to help guarantee that a transmission from thedevice is reliably received at the base station. For example, withreference to FIG. 2, if the device determines that it need a coverageextension level corresponding to a gain of six dB, the device can repeatits transmission ten times, and the base station can determine that thedevice needs a ten dB coverage extension. In one or more embodiments,the device can use the closest repetition level regardless of whetherthe extension level is greater or less than the determined extensionlevel needed. In the example in which the device determines that itneeds a six dB extension, the device can use the repetition level forthe five dB gain instead of the ten dB gain. If using a repetition leveldoes not provide reliable communication, then the device can switch tousing the next, greatest repetition level. For example, if the device iscommunicating by repeating their communication twice with mixed or poorresults, the device can switch to repeating the communication ten times,so as to help improve the reliability of the communication.

The method 600 can include, for a contention based random access mode ofoperation, a device randomly select one preamble signature sequence inthe subset of signature sequences for the corresponding repetitionlevel. The operation at 608 can include transmitting the PRACH signalusing the associated PRACH resources as described above. Note that thedevice can utilize the same signature sequence in a repeated PRACHtransmission.

The method 600 can include, upon the successful PRACH detection ondedicated resources, determining the coverage extension level requestedby the device. The base station can determine this by, for example,counting the number of repeat transmissions from the device. The basestation can communicate to the device using the same number ofrepetitions, or by transmitting a communication to device using a powerconsistent with the coverage level extension.

In a case where a coverage limited device does not receive a RandomAccess Response (RAR) communication from the base station, such as afterthe specified number of retransmission attempts (e.g., one or more), thedevice can increase the repetition level for the subsequentretransmission attempts, such as to help improve the detectionperformance.

FIG. 7 illustrates a block diagram of an example of a wired or wirelessdevice 700 in accord with one or more embodiments. The device 700 (e.g.,a machine) can operate so as to perform one or more of the techniques(e.g., methodologies) discussed herein. In alternative embodiments, thedevice 700 can operate as a standalone device or can be connected (e.g.,networked) to other machines, such as the base station 102 or the device104A-D. The device 700 can be a part of the base station 102 or thedevice 104A-D, as discussed herein. In a networked deployment, thedevice 700 can operate in the capacity of a server machine, a clientmachine, or both in server-client network environments. In an example,the device 700 can act as a peer machine in peer-to-peer (P2P) (or otherdistributed) network environment. The device 700 can include a personalcomputer (PC), a tablet PC, a set-top box (STB), a personal digitalassistant (PDA), a mobile telephone, a web appliance, a network router,switch or bridge, or any machine capable of executing instructions(sequential or otherwise) that specify actions to be taken by thatmachine, such as a base station. Further, while only a single machine isillustrated, the term “machine” shall also be taken to include anycollection of machines that individually or jointly execute a set (ormultiple sets) of instructions to perform any one or more of themethodologies discussed herein, such as cloud computing, software as aservice (SaaS), other computer cluster configurations.

Examples, as described herein, can include, or can operate on, logic ora number of components, modules, or mechanisms. Modules are tangibleentities (e.g., hardware) capable of performing specified operationswhen operating. A module includes hardware. In an example, the hardwarecan be specifically configured to carry out a specific operation (e.g.,hardwired). In an example, the hardware can include configurableexecution units (e.g., transistors, circuits, etc.) and a computerreadable medium containing instructions, where the instructionsconfigure the execution units to carry out a specific operation when inoperation. The configuring can occur under the direction of theexecutions units or a loading mechanism. Accordingly, the executionunits are communicatively coupled to the computer readable medium whenthe device is operating. In this example, the execution units can be amember of more than one module. For example, under operation, theexecution units can be configured by a first set of instructions toimplement a first module at one point in time and reconfigured by asecond set of instructions to implement a second module.

Device (e.g., computer system) 700 can include a hardware processor 702(e.g., a central processing unit (CPU), a graphics processing unit(GPU), a hardware processor core, or any combination thereof), a mainmemory 704 and a static memory 706, some or all of which can communicatewith each other via an interlink (e.g., bus) 708. The device 700 canfurther include a display unit 710, an alphanumeric input device 712(e.g., a keyboard), and a user interface (UI) navigation device 714(e.g., a mouse). In an example, the display unit 710, input device 712and UI navigation device 714 can be a touch screen display. The device700 can additionally include a storage device (e.g., drive unit) 716, asignal generation device 718 (e.g., a speaker), a network interfacedevice 720, and one or more sensors 721, such as a global positioningsystem (GPS) sensor, compass, accelerometer, or other sensor. The device700 can include an output controller 728, such as a serial (e.g.,universal serial bus (USB), parallel, or other wired or wireless (e.g.,infrared (IR), near field communication (NFC), etc.) connection tocommunicate or control one or more peripheral devices (e.g., a printer,card reader, etc.). The device 700 can include one or more radios 730(e.g., transmission, reception, or transceiver devices). The radios 730can include one or more antennas to receive signal transmissions. Theradios 730 can be coupled to or include the processor 702. The processor702 can cause the radios 730 to perform one or more transmit or receiveoperations. Coupling the radios 730 to such a processor can beconsidered configuring the radio 730 to perform such operations. Theradio 730 can be a cellular network radio configured to communicate to abase station or other component of a cellular network.

The storage device 716 can include a machine readable medium 322 onwhich is stored one or more sets of data structures or instructions 724(e.g., software) embodying or utilized by any one or more of thetechniques or functions described herein. The instructions 724 can alsoreside, completely or at least partially, within the main memory 704,within static memory 706, or within the hardware processor 702 duringexecution thereof by the device 700. In an example, one or anycombination of the hardware processor 702, the main memory 704, thestatic memory 706, or the storage device 716 can constitute machinereadable media.

While the machine readable medium 722 is illustrated as a single medium,the term “machine readable medium” can include a single medium ormultiple media (e.g., a centralized or distributed database, and/orassociated caches and servers) configured to store the one or moreinstructions 724.

The term “machine readable medium” can include any medium that iscapable of storing, encoding, or carrying instructions for execution bythe device 700 and that cause the device 700 to perform any one or moreof the techniques of the present disclosure, or that is capable ofstoring, encoding or carrying data structures used by or associated withsuch instructions. Non-limiting machine readable medium examples caninclude solid-state memories, and optical and magnetic media. In anexample, a massed machine readable medium comprises a machine readablemedium with a plurality of particles having resting mass. Specificexamples of massed machine readable media can include: non-volatilememory, such as semiconductor memory devices (e.g., ElectricallyProgrammable Read-Only Memory (EPROM), Electrically ErasableProgrammable Read-Only Memory (EEPROM)) and flash memory devices;magnetic disks, such as internal hard disks and removable disks;magneto-optical disks; and CD-ROM and DVD-ROM disks.

The instructions 724 can further be transmitted or received over acommunications network 726 using a transmission medium via the networkinterface device 720 utilizing any one of a number of transfer protocols(e.g., frame relay, internet protocol (IP), transmission controlprotocol (TCP), user datagram protocol (UDP), hypertext transferprotocol (HTTP), etc.). Example communication networks can include alocal area network (LAN), a wide area network (WAN), a packet datanetwork (e.g., the Internet), mobile telephone networks (e.g., cellularnetworks), Plain Old Telephone (POTS) networks, and wireless datanetworks (e.g., Institute of Electrical and Electronics Engineers (IEEE)802.11 family of standards known as Wi-Fi®, IEEE 802.16 family ofstandards known as WiMax®), IEEE 802.15.4 family of standards,peer-to-peer (P2P) networks, among others. In an example, the networkinterface device 720 can include one or more physical jacks (e.g.,Ethernet, coaxial, or phone jacks) or one or more antennas to connect tothe communications network 726. In an example, the network interfacedevice 720 can include a plurality of antennas to wirelessly communicateusing at least one of single-input multiple-output (SIMO),multiple-input multiple-output (MIMO), or multiple-input single-output(MISO) techniques. The term “transmission medium” shall be taken toinclude any intangible medium that is capable of storing, encoding orcarrying instructions for execution by the device 700, and includesdigital or analog communications signals or other intangible medium tofacilitate communication of such software.

Examples and Notes

The present subject matter can be described by way of several examples.

Example 1 can include or use subject matter (such as an apparatus, amethod, a means for performing acts, or a device readable memoryincluding instructions that, when performed by the device, can cause thedevice to perform acts), such as can include or use determining areceived signal strength of a reference signal transmitted from aneNodeB, determining a coverage enhancement based on the determinedsignal strength, or transmitting a signature sequence of a plurality ofsignature sequences a first repeated number of times corresponding tothe determined coverage enhancement.

Example 2 can include or use, or can optionally be combined with thesubject matter of Example 1, to include or use randomly selecting thesignature sequence from a plurality of signature sequences dedicated toprovide access to Physical Random Access Channel (PRACH) resources andwherein transmitting the signature sequence includes transmitting therandomly selected signature sequence.

Example 3 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 1-2, to include or usereceiving a broadcast indicating a plurality of coverage enhancementoptions available to the UE, wherein each coverage enhancement optionincludes a plurality of PRACH resource signature sequences split intonon-overlapping subsets of signature sequences, one subset of signaturesequences for each coverage enhancement option.

Example 4 can include or use, or can optionally be combined with thesubject matter of Example 3, to include or use, wherein the broadcastindicates that PRACH resources dedicated to human type communication UEsand PRACH resources dedicated to Machine Type Communication (MTC) UEsare orthogonal in the time domain.

Example 5 can include or use, or can optionally be combined with thesubject matter of Example 3, to include or use, wherein the broadcastindicates that PRACH resources dedicated to human type communication UEsare arranged to communicate using a first frequency band and PRACHresources dedicated to MTC UEs are arranged to communicate using asecond frequency band that does not overlap with the first frequencyband.

Example 6 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 3-5, to include or use,wherein the plurality of coverage enhancement options include a firstcoverage enhancement option including a corresponding first repetitionlevel indicating a number of times to repeat a transmission to achieve afirst coverage enhancement level and a second coverage enhancementoption including a corresponding second repetition level indicating anumber of times to repeat a transmission to achieve a second coverageenhancement level, wherein the first coverage enhancement level isgreater than the second coverage enhancement level and the firstrepetition level is greater than the second repetition level.

Example 7 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 1-6, to include or usedetermining that the repeated transmission is not being received by theeNodeB and wherein transmitting a signature sequence of the plurality ofsignature sequences includes transmitting the signature sequence asecond repeated number of times greater than the first repeated numberof times in response to determining the transmission is not beingreceived.

Example 8 can include or use subject matter (such as an apparatus, amethod, a means for performing acts, or a device readable memoryincluding instructions that, when performed by the device, can cause thedevice to perform acts), such as can include or use a processor arrangedto determine a received signal strength of a reference signaltransmitted from an eNodeB and determine a coverage enhancement based onthe determined signal strength, or a transceiver arranged to transmit asignature sequence of a plurality of signature sequences a firstrepeated number of times based on the determined coverage enhancement.

Example 9 can include or use, or can optionally be combined with thesubject matter of Example 8, to include or use, wherein the processor isarranged to randomly select the signature sequence from a plurality ofsignature sequences dedicated to provide access to Physical RandomAccess Channel (PRACH) resources and wherein the transceiver arranged totransmit the signature sequence includes the transceiver arranged totransmit the randomly selected signature sequence.

Example 10 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 8-9, to include or use,wherein the transceiver is arranged to receive a broadcast indicating aplurality of available coverage enhancement options, wherein eachcoverage enhancement option includes one or more PRACH resourcesignature sequences split into non-overlapping subsets of signaturesequences, one subset of signature sequences for each coverageenhancement option.

Example 11 can include or use, or can optionally be combined with thesubject matter of Example 10, to include or use, wherein the broadcastindicates that resources dedicated to human type communication UEs andresources dedicated to Machine Type Communication (MTC) UEs areorthogonal in the time domain.

Example 12 can include or use, or can optionally be combined with thesubject matter of Example 10, to include or use, wherein the broadcastindicates that PRACH resources dedicated to human type communication UEsare arranged to communicate using a first frequency band and PRACHresources dedicated to MTC UEs are arranged to communicate using asecond frequency band that does not overlap with the first frequencyband.

Example 13 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 10-12, to include or use,wherein the plurality of coverage enhancement options include a firstcoverage enhancement option including a corresponding first repetitionlevel indicating a number of times to repeat a transmission to achieve afirst coverage enhancement level and a second coverage enhancementoption including a corresponding second repetition level indicating anumber of times to repeat a transmission to achieve a second coverageenhancement level, wherein the first coverage enhancement level isgreater than the second coverage enhancement level and the firstrepetition level is greater than the second repetition level.

Example 14 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 8-13, to include or use,wherein the processor is arranged to determine that the repeatedtransmission is not being received by the eNodeB and wherein thetransceiver is arranged to transmit a signature sequence of theplurality of signature sequences a second repeated number of timesgreater than the first repeated number of times in response todetermining the transmission is not being received.

Example 15 can include or use subject matter (such as an apparatus, amethod, a means for performing acts, or a device readable memoryincluding instructions that, when performed by the device, can cause thedevice to perform acts), such as can include or use a transceiverarranged to receive a transmission from a UE, wherein the transmissionis repeated a number of times, and a processor arranged to determine acoverage enhancement of the UE based on the number of times thetransmission is repeated, and wherein the transceiver is configured torepeat transmissions to the UE the same number of times as the receivedtransmission from the UE.

Example 16 can include or use, or can optionally be combined with thesubject matter of Example 15, to include or use, wherein the processoris arranged to assign a signature sequence of a plurality of signaturesequences dedicated to provide access to Physical Random Access Channel(PRACH) resources to the UE based on the number of received, repeatedtransmissions.

Example 17 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 15-16, to include or use,wherein the transceiver is arranged to transmit a broadcast indicating aplurality of available coverage enhancement options, wherein eachcoverage enhancement option includes one or more PRACH resourcesignature sequences split into non-overlapping subsets of signaturesequences, one subset of signature sequences for each coverageenhancement option.

Example 18 can include or use, or can optionally be combined with thesubject matter of Example 17, to include or use, wherein the transceiverarranged to transmit the broadcast includes the transceiver arranged totransmit a broadcast that indicates that resources dedicated to humantype communication UEs and resources dedicated to Machine TypeCommunication (MTC) UEs are orthogonal in the time domain.

Example 19 can include or use, or can optionally be combined with thesubject matter of Example 17, to include or use, wherein the transceiverarranged to transmit the broadcast includes the transceiver arranged totransmit a broadcast that indicates that resources dedicated to humantype communication UEs are arranged to communicate using a firstfrequency band and resources dedicated to MTC UEs are arranged tocommunicate using a second frequency band that does not overlap with thefirst frequency band.

Example 20 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 17-19, to include or use,wherein the plurality of coverage enhancement options include a firstcoverage enhancement option including a corresponding first repetitionlevel indicating a number of times to repeat a transmission to achieve afirst coverage enhancement level and a second coverage enhancementoption including a corresponding second repetition level indicating anumber of times to repeat a transmission to achieve a second coverageenhancement level, wherein the first coverage enhancement level isgreater than the second coverage enhancement level and the firstrepetition level is greater than the second repetition level.

Example 21 can include or use subject matter (such as an apparatus, amethod, a means for performing acts, or a device readable memoryincluding instructions that, when performed by the device, can cause thedevice to perform acts), such as can include or use receiving atransmission from a UE, wherein the transmission is repeated a number oftimes, determining a coverage enhancement of the UE based on the numberof times the transmission is repeated, repeating a transmission to theUE the same number of times as the number of times the receivedtransmission is repeated from the UE.

Example 22 can include or use, or can optionally be combined with thesubject matter of Example 21, to include or use, assigning a signaturesequence of a plurality of signature sequences dedicated to provideaccess to Physical Random Access Channel (PRACH) resources to the UEbased on the number of received, repeated transmissions.

Example 23 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 21-22, to include or use,transmitting a broadcast indicating a plurality of available coverageenhancement options, wherein each coverage enhancement option includesone or more PRACH resource signature sequences split intonon-overlapping subsets of signature sequences, one subset of signaturesequences for each coverage enhancement option.

Example 24 can include or use, or can optionally be combined with thesubject matter of Example 23, to include or use, wherein transmittingthe broadcast includes transmitting a broadcast that indicates thatresources dedicated to human type communication UEs and resourcesdedicated to Machine Type Communication (MTC) UEs are orthogonal in thetime domain.

Example 25 can include or use, or can optionally be combined with thesubject matter of Example 23, to include or use, wherein transmittingthe broadcast includes transmitting a broadcast that indicates thatresources dedicated to human type communication UEs are arranged tocommunicate using a first frequency band and resources dedicated to MTCUEs are arranged to communicate using a second frequency band that doesnot overlap with the first frequency band.

Example 26 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 23-25, to include or use,wherein the plurality of coverage enhancement options include a firstcoverage enhancement option including a corresponding first repetitionlevel indicating a number of times to repeat a transmission to achieve afirst coverage enhancement level and a second coverage enhancementoption including a corresponding second repetition level indicating anumber of times to repeat a transmission to achieve a second coverageenhancement level, wherein the first coverage enhancement level isgreater than the second coverage enhancement level and the firstrepetition level is greater than the second repetition level.

The above detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments in which methods,apparatuses, and systems discussed herein can be practiced. Theseembodiments are also referred to herein as “examples.” Such examples caninclude elements in addition to those shown or described. However, thepresent inventors also contemplate examples in which only those elementsshown or described are provided. Moreover, the present inventors alsocontemplate examples using any combination or permutation of thoseelements shown or described (or one or more aspects thereof), eitherwith respect to a particular example (or one or more aspects thereof),or with respect to other examples (or one or more aspects thereof) shownor described herein.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In this document, the terms “including” and “inwhich” are used as the plain-English equivalents of the respective terms“comprising” and “wherein.” Also, in the following claims, the terms“including” and “comprising” are open-ended, that is, a system, device,article, composition, formulation, or process that includes elements inaddition to those listed after such a term in a claim are still deemedto fall within the scope of that claim. Moreover, in the followingclaims, the terms “first,” “second,” and “third,” etc. are used merelyas labels, and are not intended to impose numerical requirements ontheir objects.

As used herein, a “-” (dash) used when referring to a reference numbermeans “or”, in the non-exclusive sense discussed in the previousparagraph, of all elements within the range indicated by the dash. Forexample, 103A-B means a nonexclusive “or” of the elements in the range{103A, 103B}, such that 103A-103B includes “103A but not 103B”, “103Bbut not 103A”, and “103A and 103B”.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) can be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. The Abstract is provided to complywith 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims. Also, in the above Detailed Description,various features can be grouped together to streamline the disclosure.This should not be interpreted as intending that an unclaimed disclosedfeature is essential to any claim. Rather, inventive subject matter canlie in less than all features of a particular disclosed embodiment.Thus, the following claims are hereby incorporated into the DetailedDescription as examples or embodiments, with each claim standing on itsown as a separate embodiment, and it is contemplated that suchembodiments can be combined with each other in various combinations orpermutations. The scope of the invention should be determined withreference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

What is claimed is:
 1. A method performed by a User Equipment (UE)comprising: determining a received signal strength of a reference signaltransmitted from an eNodeB; determining a coverage enhancement based onthe determined signal strength; and transmitting a signature sequence ofa plurality of signature sequences a first repeated number of timescorresponding to the determined coverage enhancement.
 2. The method ofclaim 1, further comprising randomly selecting the signature sequencefrom a plurality of signature sequences dedicated to provide access toPhysical Random Access Channel (PRACH) resources and whereintransmitting the signature sequence includes transmitting the randomlyselected signature sequence.
 3. The method of claim 1, furthercomprising receiving a broadcast indicating a plurality of coverageenhancement options available to the UE, wherein each coverageenhancement option includes a plurality of PRACH resource signaturesequences split into non-overlapping subsets of signature sequences, onesubset of signature sequences for each coverage enhancement option. 4.The method of claim 3, wherein the broadcast indicates that PRACHresources dedicated to human type communication UEs and resourcesdedicated to Machine Type Communication (MTC) UEs are orthogonal in thetime domain.
 5. The method of claim 3, wherein the broadcast indicatesthat resources dedicated to human type communication UEs are arranged tocommunicate using a first frequency band and resources dedicated to MTCUEs are arranged to communicate using a second frequency band that doesnot overlap with the first frequency band.
 6. The method of claim 3,wherein the plurality of coverage enhancement options include a firstcoverage enhancement option including a corresponding first repetitionlevel indicating a number of times to repeat a transmission to achieve afirst coverage enhancement level and a second coverage enhancementoption including a corresponding second repetition level indicating anumber of times to repeat a transmission to achieve a second coverageenhancement level, wherein the first coverage enhancement level isgreater than the second coverage enhancement level and the firstrepetition level is greater than the second repetition level.
 7. Themethod of claim 3, further comprising determining that the repeatedtransmission is not being received by the eNodeB and whereintransmitting a signature sequence of the plurality of signaturesequences includes transmitting the signature sequence a second repeatednumber of times greater than the first repeated number of times inresponse to determining the transmission is not being received.
 8. AUser Equipment (UE) comprising: a processor arranged to determine areceived signal strength of a reference signal transmitted from aneNodeB and determine a coverage enhancement based on the determinedsignal strength; and a transceiver arranged to transmit a signaturesequence of a plurality of signature sequences a first repeated numberof times based on the determined coverage enhancement.
 9. The UE ofclaim 8, wherein the processor is arranged to randomly select thesignature sequence from a plurality of signature sequences dedicated toprovide access to Physical Random Access Channel (PRACH) resources andwherein the transceiver arranged to transmit the signature sequenceincludes the transceiver arranged to transmit the randomly selectedsignature sequence.
 10. The UE of claim 9, wherein the transceiver isarranged to receive a broadcast indicating a plurality of availablecoverage enhancement options, wherein each coverage enhancement optionincludes one or more PRACH resource signature sequences split intonon-overlapping subsets of signature sequences, one subset of signaturesequences for each coverage enhancement option.
 11. The UE of claim 10,wherein the broadcast indicates that resources dedicated to human typecommunication UEs and resources dedicated to Machine Type Communication(MTC) UEs are orthogonal in the time domain.
 12. The UE of claim 10,wherein the broadcast indicates that resources dedicated to human typecommunication UEs are arranged to communicate using a first frequencyband and resources dedicated to MTC UEs are arranged to communicateusing a second frequency band that does not overlap with the firstfrequency band.
 13. The UE of claim 10, wherein the plurality ofcoverage enhancement options include a first coverage enhancement optionincluding a corresponding first repetition level indicating a number oftimes to repeat a transmission to achieve a first coverage enhancementlevel and a second coverage enhancement option including a correspondingsecond repetition level indicating a number of times to repeat atransmission to achieve a second coverage enhancement level, wherein thefirst coverage enhancement level is greater than the second coverageenhancement level and the first repetition level is greater than thesecond repetition level.
 14. The UE of claim 10, wherein the processoris arranged to determine that the repeated transmission is not beingreceived by the eNodeB and wherein the transceiver is arranged totransmit a signature sequence of the plurality of signature sequences asecond repeated number of times greater than the first repeated numberof times in response to determining the transmission is not beingreceived.
 15. A non-transitory computer readable storage deviceincluding instructions stored thereon, which when executed by a machine,cause the machine to perform operations comprising: determining areceived signal strength of a reference signal transmitted from aneNodeB; determining a coverage enhancement based on the determinedsignal strength; and transmitting a signature sequence of a plurality ofsignature sequences a first repeated number of times corresponding tothe determined coverage enhancement.
 16. The storage device of claim 15,further comprising instructions stored thereon, which when executed bythe machine cause the machine to perform operations comprising: randomlyselecting the signature sequence from a plurality of signature sequencesdedicated to provide access to Physical Random Access Channel (PRACH)resources and wherein the instructions for transmitting the signaturesequence include instructions, which when executed by the machine, causethe machine to perform operations comprising transmitting the randomlyselected signature sequence.
 17. The storage device of claim 1, furthercomprising instructions, which when executed by the machine, cause themachine to perform operations comprising receiving a broadcastindicating a plurality of coverage enhancement options available to theUE, wherein each coverage enhancement option includes one or more PRACHresource signature sequences split into non-overlapping subsets ofsignature sequences, one subset of signature sequences for each coverageenhancement option.
 18. The storage device of claim 17, wherein thebroadcast indicates that PRACH resources dedicated to human typecommunication UEs and PRACH resources dedicated to Machine TypeCommunication (MTC) UEs are orthogonal in the time domain.
 19. Thestorage device of claim 17, wherein the broadcast indicates that PRACHresources dedicated to human type communication UEs are arranged tocommunicate using a first frequency band and PRACH resources dedicatedto MTC UEs are arranged to communicate using a second frequency bandthat does not overlap with the first frequency band.
 20. The storagedevice of claim 17, wherein the plurality of coverage enhancementoptions include a first coverage enhancement option including acorresponding first repetition level indicating a number of times torepeat a transmission to achieve a first coverage enhancement level anda second coverage enhancement option including a corresponding secondrepetition level indicating a number of times to repeat a transmissionto achieve a second coverage enhancement level, wherein the firstcoverage enhancement level is greater than the second coverageenhancement level and the first repetition level is greater than thesecond repetition level.